1. Field of the Invention
The present invention relates to constant velocity joints generally and, more particularly, to a novel boot retainer for such joints which provides excellent sealing and which permits greater operating angles than are achievable with conventional boot retainers.
2. Background Art
Constant velocity joints are well known devices for transmitting rotational motion uniformly from a driving member to a driven member, the two members having axes of rotation in angular relation therebetween. Typically, the driving member as a shaft extending from an engine or a transmission and the driven member is a wheel or a shaft extending to a machine or wheel being driven by the engine.
Such joints are widely used in front wheel drive vehicles. In this application, there is a need to transmit rotary motion from the transmission to the front wheels, both the transmission and front wheels remaining in relatively fixed vertical planes, but being relatively vertically displaceable from one another. Since the distance between the transmission and the front wheels is short, the shaft extending therebetween can assume rather sharp angles upward and downward when the vehicle is moving, compared to a resting position when the vehicle is not moving. To accommodate this relative motion, constant velocity joints are provided at either end of the shaft to accommodate the angular displacement and also to accommodate horizontal (slip) displacement.
Because of the high degree of motion between moving parts within a constant velocity joint, it is necessary that it be well lubricated and that dirt and dust be excluded therefrom. In order to accomplish these objectives, a resilient boot is provided to seal the joint. The boot is almost always secured to a cylindrical shaft member by means of a tightened metal band. In some cases, the boot is secured to the joint also by means of a metal band tightened about a suitable cylindrical surface, which may comprise a metal stamping extending from the housing of the constant velocity joint. In other cases, the boot is secured to the joint by an annular retaining ring having a plurality of apertures formed therethrough, which ring mates with a flat annular flange formed on the end of the boot orthogonal to the major axis thereof. The flange has a corresponding plurality of apertures formed therethrough and a plurality of fasteners extends through the apertures of the retaining ring and the flange into the housing of the constant velocity joint.
Such conventional means of securing constant velocity joint boots have a number of disadvantages, among which is that operating angles are limited at various slip positions. A further disadvantage of some conventional means is that there is resilient material (a portion of the boot) disposed between the clamping member and the member to which the boot is being secured. The latter arrangement can lead to the boot material disposed between the metal surfaces being overcompressed which can shorten the life of the boot. In the case of a clamping surface comprising a metal stamping extending from the constant velocity joint, extreme operating angles may cause the shaft to strike the end of the stamping. Also, the latter arrangement relies on a relatively ineffective metal-to-metal seal to retain lubricant.
Some conventional constant velocity joint boots intended for high speeds are surrounded by cylindrical shells which are provided to prevent the boots from ballooning outward at high speeds. Typically, the boots are bonded, crimped, or otherwise attached to the inside surface of these shells. The latter arrangement is disadvantageous in that such attachment limits the operating axial motion and operating angle of the boot.
Accordingly, it is a principal object of the present invention to provide retaining means for securing constant velocity joint boots that permits greater operating angles than can be achieved with conventional retaining means.
A further object of the invention is to provide such retaining means that prevents overcompression of the boot material when the boot is secured to the joint.
An additional object of the invention is to provide such retaining means that includes, as an integral part thereof, a shell to prevent ballooning of the boot, which shell is unattached to the boot to permit greater operating angles and free axial movement of the boot.
Another object of the invention is to provide such retaining means and a boot that can be easily retrofitted to existing constant velocity joints.
Other objects of the present invention, as well as particular features, elements, and advantages thereof, will be elucidated in, or be apparent from, the following description and the accompanying drawing figures.